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drm/vc4: Fix NULL pointer dereference in vc4_save_hang_state()

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When saving BOs in the hang state we skip one entry of the
kernel_state->bo[] array, thus leaving it to NULL. This leads to a NULL
pointer dereference when, later in this function, we iterate over all
BOs to check their ->madv state.

Fixes: ca26d28bba ("drm/vc4: improve throughput by pipelining binning and rendering jobs")
Cc: <stable@vger.kernel.org>
Signed-off-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
Reviewed-by: Eric Anholt <eric@anholt.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20180118145821.22344-1-boris.brezillon@free-electrons.com
This commit is contained in:
Boris Brezillon 2018-01-18 15:58:21 +01:00 committed by Eric Anholt
parent f61145f1a4
commit 17b11b76b8
1 changed files with 6 additions and 6 deletions
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12
drivers/gpu/drm/vc4/vc4_gem.c
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@ -146,7 +146,7 @@ vc4_save_hang_state(struct drm_device *dev)
struct vc4_exec_info *exec[2];
struct vc4_bo *bo;
unsigned long irqflags;
unsigned int i, j, unref_list_count, prev_idx;
unsigned int i, j, k, unref_list_count;
kernel_state = kcalloc(1, sizeof(*kernel_state), GFP_KERNEL);
if (!kernel_state)
@ -182,7 +182,7 @@ vc4_save_hang_state(struct drm_device *dev)
return;
}
prev_idx = 0;
k = 0;
for (i = 0; i < 2; i++) {
if (!exec[i])
continue;
@ -197,7 +197,7 @@ vc4_save_hang_state(struct drm_device *dev)
WARN_ON(!refcount_read(&bo->usecnt));
refcount_inc(&bo->usecnt);
drm_gem_object_get(&exec[i]->bo[j]->base);
kernel_state->bo[j + prev_idx] = &exec[i]->bo[j]->base;
kernel_state->bo[k++] = &exec[i]->bo[j]->base;
}
list_for_each_entry(bo, &exec[i]->unref_list, unref_head) {
@ -205,12 +205,12 @@ vc4_save_hang_state(struct drm_device *dev)
* because they are naturally unpurgeable.
*/
drm_gem_object_get(&bo->base.base);
kernel_state->bo[j + prev_idx] = &bo->base.base;
j++;
kernel_state->bo[k++] = &bo->base.base;
}
prev_idx = j + 1;
}
WARN_ON_ONCE(k != state->bo_count);
if (exec[0])
state->start_bin = exec[0]->ct0ca;
if (exec[1])